On to Richmond in 1864: The Overland Campaign

Col. Mosby abandoned the use of sabers and outfitted his partisan rangers with pistols instead
Source: Illustrated London News, The Civil War in America: Capture of a United States' Dragoon by Guerrilla Horsemen of Virginia (July 27, 1861)

General Grant chose to start the 1864 campaign on the west side of the Confederate line on the Rapidan River and rely on wagons to transport supplies, rather than use steamboats on the Potomac River to bring food/ammunition to the base at Belle Plain
Source: Library of Congress, Map showing from Richmond to Fredericksburg, VA

Federal forces crossed the Rapidan River at the start of the 1864 Overland Campaign, and General Lee attacked while different units were isolated from each other on the poor roads in The Wilderness
Source: Library of Congress, Map of a portion of the Rappahannock River and vicinity, Virginia

Union forces crossed the Rappahannock River on pontoon bridges at Fredericksburg
Source: Alexander Gardner, Gardner's Photographic Sketch Book of the War

a pontoon bridge was needed for the Union Army to cross the James River in 1864
Source: National Archives, Pontoon bridge across James River, 1864

Source: American Battlefield Trust, The Wilderness to Cold Harbor, Grant's Overland Campaign: Animated Battle Map